Griffin had worked at NASA prior to serving as NASA Administrator, including as Associate Administrator for Exploration. When he was nominated as NASA chief, he was head of the Space Department at the Johns Hopkins UniversityApplied Physics Laboratory (APL) in Laurel, Maryland. While he describes himself modestly as a "simple aerospace engineer from a small town", Griffin has held several high-profile political appointments. In 2007 he was included in the TIME 100, the magazine's list of the 100 most influential people.[2]

Griffin's appointment as Administrator was associated with a significant shift in the direction of the agency. He began signaling intended changes at his Senate confirmation hearing.

Griffin's prior experience includes working at the Applied Physics Laboratory (APL) in the 1980s, when he helped design the successful Delta 180 series of missile-defense technology satellites for the Strategic Defense Initiative Organization. After leaving APL in 1986, he served as the Strategic Defense Initiative Organization's deputy for technology, then as the chief engineer and later Associate Administrator for Exploration at NASA Headquarters.

Griffin has been a professor at various universities, teaching courses in spacecraft design, applied mathematics, guidance and navigation, compressible flow, computational fluid dynamics, spacecraft attitude control, astrodynamics, and introductory aerospace engineering. He is the lead author of more than two dozen technical papers, and is co-author with James R. French of the graduate astronautical engineering textbook, "Space Vehicle Design". ISBN1-56347-539-1 Griffin is also a general aviation flight instructor and pilot, and owner of a small airplane, a Beech Bonanza.

In 2004 testimony to Congress on the future of human spaceflight, he stated, "for me the single overarching goal of human space flight is the human settlement of the Solar System, and eventually beyond. I can think of no lesser purpose sufficient to justify the difficulty of the enterprise, and no greater purpose is possible." In his testimony he also advocated heavy-lift launch capabilities, development of space qualified nuclear power systems, in situ resource utilization, and cost-effective medium-size transport to low Earth orbit.

Griffin told a Senate subcommittee that the first book he ever received was a book on astronomy and space when he was five years old, and "I was absolutely fascinated by it, and from that time forward, I never considered for myself anything other than being a scientist or engineer or mathematician and involving myself in the space business."

Griffin and astronaut Owen K. Garriott were the team co-leaders for a study commissioned by the Planetary Society entitled "Extending Human Presence Into the Solar System" in 2004. Griffin cited this study in his first press conference as NASA Administrator to answer a question about sending humans to Mars, saying "I would urge you to download that report from the website because I don't have any better thinking to offer you than what I put into that report."[7]

Griffin was one of the original signatories of the Mars Society, which is dedicated to human settlement of Mars. Mars Society president Robert Zubrin recounts in his book, The Case for Mars, that in 1991, after Zubrin presented his ideas about a Mars mission architecture with Griffin, then NASA Associate Administrator for Exploration, Griffin presented these ideas to then NASA Administrator Daniel Goldin.

Michael Griffin was formally sworn in by Vice President Dick Cheney on June 28, 2005.

On March 11, 2005, President George W. Bush announced his intention to nominate Griffin to serve as the 11th Administrator of NASA. He was confirmed by the Senate on April 13, 2005. Griffin was subsequently sworn in by Vice-President Dick Cheney, a rarity for a NASA Administrator and signifying the importance NASA held to the Bush Administration. The Administration even recalled its former NASA transition team director and chief of staff, Courtney Stadd,[8] to assist Griffin.[9]

On September 28, 2007, Griffin said that NASA aims to put a man on Mars by 2037.[10] In an interview with The Guardian in July 2008 Griffin stated that an opportunity to push on to Mars by extending the Apollo program was squandered by a change in focus to Shuttle and space station programs that only reached orbit: "I spent some time analysing what we could have done had we used the budgets we received to explore the capabilities inherent in the Apollo hardware after it was built. The short answer is we would have been on Mars 15 or 20 years ago, instead of circling endlessly in low Earth orbit."[11]

It was widely known that Griffin hoped to keep his job under President Barack Obama so that Constellation and NASA's other programs could maintain their steady progress.[12][13][14] In a phone call on the day after the election, Senator Bill Nelson (D, FL) requested of Lori Garver, who led the incoming Obama Administration's Transition Team, that the Administration allow Griffin to remain as NASA Administrator to provide programmatic and management continuity. However, his resignation (required of and offered by all agency heads due to an incoming President) was accepted. In part, this was because of disagreements between Griffin and Garver over the state of Project Constellation. Griffin gave a farewell address to NASA on 16 January 2009, in which he praised NASA for its recovery from the Columbia disaster and urged employees to support the new administrator, whoever it may be.[15][16] He left office the day President Obama was inaugurated.

Griffin has been criticized by space research organizations such as NASA Ames Research Center life sciences group for shifting portions of NASA's budget from science to manned spaceflight.[17] Griffin had stated that he would not shift "one thin dime" of funding from science to human spaceflight, but less than six months later, in February 2006, after NASA Constellation funding did not reach requested levels, NASA revealed a budget that reduced space research funding by about 25%, including indefinite deferrals of planned programs such as the Jupiter Icy Moons Orbiter, the Terrestrial Planet Finder, and the Space Interferometry Mission.[18] The logic was that funding Project Constellation, a presidentially mandated program, was the top priority of the space agency.

Funding for a New York company to research the Prometheus space nuclear program has also been put on hold, although Griffin has said he is anxious to pursue Prometheus after the earlier-priority development of the new spacecraft is completed.[citation needed] Earlier, in November 2005, funding for life science research conducted largely out of Ames Research Center was cut by 80%, prompting representatives of the Ames life sciences group to write a scathing letter to Griffin criticizing this cut.[17]

The NASA field centers focused mainly on science rather than on human spaceflight, such as Ames and Glenn Research Center, have seen general budgetary downsizing, and many science contracts with outside researchers have been canceled.[19] Griffin attributed these cuts, along with cuts in the human spaceflight budget, as being necessitated by a $3.2 billion shortfall.[20] The National Research Council also concluded that NASA's total funding has not been enough to fulfill all its mandates and remain strong in science.[21] However, during Griffin's term, science budgets were, as a percentage of NASA's total budget, inline with those during Project Apollo. There has been some discussion, after the release of the Summary Report by the Human Space Flight Committee[22] that NASA has not been funded sufficiently to pursue a strong science program while continuing to focus on aeronautics and space exploration, the two key mission of the National Aeronautics and Space Administration.

Limitations on NASA's budget include a mandated continuation of the Space Shuttle program, including safety upgrades and testing; the mandated construction of the International Space Station; the mandated development of the Vision for Space Exploration architecture; programs outside of human spaceflight, consisting of science research and aeronautics research; and an ever-increasing share of NASA's budget devoted to line-item earmarks sometimes characterized as pork barrel spending.

The Vision for Space Exploration, announced by President Bush in 2004, mandated that NASA must use the space shuttle to finish construction of the International Space Station by the end of 2010. By June 2006, due to ongoing concerns with the safety of the Shuttle in the wake of the Columbia disaster, only one flight had been performed. Per the Presidential mandate of the Vision for Space Exploration, Griffin mandated that 18 more shuttle flights be performed in the remaining four and a half years.

Griffin approved the launch of the space shuttle Discovery for July 2006 to perform the second return-to-flight mission, overriding the NASA Chief Safety and Mission Assurance Officer, Bryan O'Connor. Although O'Connor said there were still unresolved concerns that foam insulation could break off of the external fuel tank and damage the orbiter, Griffin characterized the risk as acceptable, arguing that it would be better to test one change at a time. With that flight NASA was testing the removal of protuberance air-load ramps from cable and fuel line fittings on the exterior of the external fuel tank.[23] This launch proved that the changes made to prevent shedding of foam at the air-load ramps were successful, allowing the Shuttle program to work towards completion of the ISS by the presidentially mandated year of 2010. The construction of the ISS was actually completed in early 2011, and then the Space Shuttle system was retired.

I have no doubt that global—that a trend of global warming exists. I am not sure that it is fair to say that it is a problem we must wrestle with. To assume that it is a problem is to assume that the state of Earth's climate today is the optimal climate, the best climate that we could have or ever have had and that we need to take steps to make sure that it doesn't change.

First of all, I don't think it's within the power of human beings to assure that the climate does not change, as millions of years of history have shown, and second of all, I guess I would ask which human beings - where and when - are to be accorded the privilege of deciding that this particular climate that we have right here today, right now is the best climate for all other human beings. I think that's a rather arrogant position for people to take.[24]

Some climate scientists referred to his remarks as ignorant.[25] In particular, James E. Hansen, NASA's top official on climate change, said Griffin's comments showed "arrogance and ignorance", as millions will likely be harmed by global warming.[26]Jerry Mahlman, a scientist at the National Center for Atmospheric Research, said that Griffin was either "totally clueless" or "a deep antiglobal warming ideologue".[27]

Unfortunately, this is an issue which has become far more political than technical, and it would have been well for me to have stayed out of it." "All I can really do is apologize to all you guys.... I feel badly that I caused this amount of controversy over something like this.[25]

On April 14, 2009, Griffin accepted a position as eminent scholar and a professor of mechanical and aerospace engineering at the University of Alabama in Huntsville.[28] The university established the eminent scholar position in 1986.[29] Griffin has established the Center for System Studies at the university, which will address the need for "systems thinking" in industry and the government. System studies involve research to understand the many complex ways that technology, nature, people, and society interact so that the workings of an engineered solution are more predictable and more desirable. UA Huntsville is a Space Grant university, and has a history of cooperation with both NASA at the nearby Marshall Space Flight Center, and the U.S. Army Aviation and Missile Command at Redstone Arsenal. The campus serves as the anchor tenant in Cummings Research Park, the second largest university research park in the United States.

On August 14, 2012, the Schafer Corporation announced that Griffin would assume the role of Chairman and Chief Executive Officer at the company.[31] The Schafer Corporation is a "leading-edge technology company providing high-quality products and professional services to government and industry customers". It was founded in 1972.[32]

Griffin is the recipient of numerous honors and awards, including the Defense Department's highest award which can be conferred on a non-government employee, Distinguished Public Service Medal (1986); the AIAA Space Systems Medal (1988), the Significant Technical Accomplishment Award (Delta 183 Mission Team) from the American Defense Preparedness Association (1989); the NASA Exceptional Achievement Medal (1994); the Goddard Astronautics Award (2007); and selection by Time Magazine as one of the 100 Most Influential People of 2008. Griffin received the Rotary National Award for Space Achievement's National Space Trophy in May 2009.[35]

On March 13, 2008, Griffin was awarded the title of 74th honorary chancellor at Florida Southern College during its annual Founder's Day Ceremony.